TWI788918B - Bonding structure and electronic device - Google Patents

Abstract

A bonding structure includes a substrate, a first sensing electrode layer, a second sensing electrode layer, an optical film layer, and a protective layer. The substrate has opposite first and second surface. A sensing area and a bonding area are defined on the substrate. The first sensing electrode layer is disposed on the first surface. The second sensing electrode layer is disposed on the second surface. The optical film layer covers the first sensing electrode layer and has a first bonding opening located in the bonding area. The protective layer covers the second sensing electrode layer and has a second bonding opening located in the bonding area. The first and second bonding openings respectively expose a part of the first sensing electrode layer and a part of the second sensing electrode layer, and are misaligned in a direction perpendicular to the first surface or the second surface.

Description

Junction structure and electronic device

The disclosure relates to a bonding structure and an electronic device.

Recently, electronic products with foldable screens have been launched on the market. In order to achieve the foldable effect, the substrates of some existing touch or pressure-sensitive modules of foldable screens are realized by using plastic films (such as polymer films). In addition to flexibility, this layer of film needs to achieve thin thickness, high hardness, high temperature resistance and high light transmission.

However, when the edge of the thin substrate is bumped, cracks are likely to occur, which may affect the sensing function of the sensing electrodes disposed on the substrate. Not only that, when bonding with a flexible circuit board, the aforementioned thin substrate is also prone to cracks due to the pressing force, which may affect the signal transmission function between the sensing electrodes disposed on the substrate and the flexible circuit board . Although the prior art CN101581995B discloses double-sided bonding technology, it does not teach how to overcome cracks in thin substrates caused by bonding.

Therefore, how to propose a joint structure and electronic device that can solve the above problems is one of the problems that the industry is eager to invest in research and development resources to solve.

In view of this, one purpose of the present disclosure is to provide a bonding structure and an electronic device that can solve the above problems.

In order to achieve the above object, according to an embodiment of the present disclosure, a bonding structure includes a substrate, a first sensing electrode layer, a second sensing electrode layer, an optical film layer, and a protective layer. The substrate has a first surface and a second surface opposite to each other. A sensing region and a bonding region are defined on the substrate. The first sensing electrode layer is disposed on the first surface. The second sensing electrode layer is disposed on the second surface. The optical film layer covers the first sensing electrode layer and has a first joint opening located in the joint area. The protection layer covers the second sensing electrode layer and has a second joint opening located in the joint area. The first joint opening and the second joint opening respectively expose a part of the first sensing electrode layer and a part of the second sensing electrode layer, and are dislocated in a direction perpendicular to the first surface or the second surface.

In one or more embodiments of the present disclosure, the projections of the first joint opening and the second joint opening in the aforementioned direction are separated from each other.

In one or more embodiments of the present disclosure, the optical film layer and the protective layer respectively have a portion located between the first joint opening and the second joint opening. These portions overlap in the aforementioned direction.

In one or more implementations of the present disclosure, at least one of the first sensing electrode layer and the second sensing electrode layer is a silver nanowire electrode layer.

In one or more embodiments of the present disclosure, the substrate is a flexible substrate.

In one or more embodiments of the present disclosure, the material of the substrate includes cycloolefin polymer. The thickness of the substrate is equal to or less than 25 microns.

In one or more embodiments of the present disclosure, the material of the substrate includes colorless polyimide. The thickness of the substrate is equal to or less than 12.5 microns.

In one or more embodiments of the present disclosure, the optical film layer includes a pressure-sensitive adhesive layer, a cover layer, at least one phase retarder, and a polyvinyl alcohol layer. The covering layer is arranged on the side of the pressure-sensitive adhesive layer away from the substrate. The phase retarder is arranged between the pressure-sensitive adhesive layer and the covering layer. The polyvinyl alcohol layer is arranged between the covering layer and the phase retarder.

In order to achieve the above object, according to an embodiment of the present disclosure, an electronic device includes the aforementioned bonding structure, a flexible circuit board, a display module, and a cover plate. The flexible circuit board includes a first joint part and a second joint part. The first bonding part bonds a portion of the first sensing electrode layer exposed by the first bonding opening. The second bonding part bonds a portion of the second sensing electrode layer exposed by the second bonding opening. The display module is arranged on the side of the protective layer away from the substrate. The cover plate is arranged on the side of the optical film layer away from the base material.

In one or more embodiments of the present disclosure, the electronic device further includes a reinforcing layer. The reinforcing layer is arranged between the protective layer and the display module.

In one or more embodiments of the present disclosure, the electronic device further includes an adhesive layer. The adhesive layer is arranged between the reinforcement layer and the display module.

In one or more embodiments of the present disclosure, the electronic device further includes an adhesive layer. The adhesive layer is arranged between the protective layer and the display module, and is arranged side by side with the reinforcing layer.

To sum up, in the joint structure and the electronic device of the present disclosure, the first joint opening of the optical film layer and the second joint opening of the protective layer are misaligned in a direction substantially perpendicular to the substrate to achieve substantial The upper local dislocation is thickened, which can effectively increase the structural strength of the bonding area of the base material. Thereby, when the edge of the substrate is hit or the bonding area is bonded with the flexible circuit board, cracks in the substrate can be effectively avoided, thereby ensuring that the first sensing electrode layer and the second sensing electrode layer disposed on the substrate are Measuring the sensing function and signal transmission function of the electrode layer.

The above description is only used to explain the problems to be solved by the present disclosure, the technical means to solve the problems, and the effects thereof, etc. The specific details of the present disclosure will be introduced in detail in the following implementation methods and related drawings.

The following will disclose multiple implementations of the present disclosure with diagrams, and for the sake of clarity, many practical details will be described together in the following description. However, it should be understood that these practical details should not be used to limit the present disclosure. That is to say, in some embodiments of the present disclosure, these practical details are unnecessary. In addition, for the sake of simplifying the drawings, some well-known structures and components will be shown in a simple and schematic manner in the drawings.

Please refer to Figure 1A, Figure 1B and Figure 1C. FIG. 1A is a schematic side view of an electronic device 100 according to an embodiment of the present disclosure. FIG. 1B is a partial cross-sectional view of the electronic device 100 in FIG. 1A , which corresponds to the position indicated by the line segment 1B-1B in FIG. 2 . FIG. 1C is another partial cross-sectional view of the electronic device 100 in FIG. 1A , which corresponds to the position indicated by the line segment 1C-1C in FIG. 2 . As shown in FIG. 1A to FIG. 1C , in this embodiment, the electronic device 100 includes a bonding structure 110 , a flexible circuit board 120 , a display module 130 and a cover plate 140 . The flexible circuit board 120 is bonded to the bonding structure 110 . The display module 130 and the cover plate 140 are respectively disposed on opposite sides of the joint structure 110 . Specifically, the display module 130 is fixed to the joint structure 110 through the adhesive layer 150a, and the cover plate 140 is fixed to the joint structure 110 through the adhesive layer 150b.

In some embodiments, at least one of the adhesive layers 150a, 150b is optical clear adhesive (OCA), but the present disclosure is not limited thereto.

In detail, the bonding structure 110 includes a substrate 111 , a first sensing electrode layer 112 , a second sensing electrode layer 113 , an optical film layer 114 and a protection layer 115 . The substrate 111 has a first surface 111a and a second surface 111b opposite to each other. The first sensing electrode layer 112 is disposed on the first surface 111a. The second sensing electrode layer 113 is disposed on the second surface 111b. The optical film layer 114 covers the first sensing electrode layer 112 . The protection layer 115 covers the second sensing electrode layer 113 . The display module 130 is disposed on a side of the protective layer 115 away from the substrate 111 . The cover plate 140 is disposed on a side of the optical film layer 114 away from the substrate 111 .

In some embodiments, at least one of the first sensing electrode layer 112 and the second sensing electrode layer 113 may be a nano silver wire (silver nano wires, SNW; also known as AgNW) electrode layer, a metal grid Or include indium tin oxide (ITO) electrode layer, but the present disclosure is not limited thereto. In the embodiment in which at least one of the first sensing electrode layer 112 and the second sensing electrode layer 113 is a nano silver wire electrode layer, the first sensing electrode layer 112 and the second sensing electrode layer 113 At least one of the foregoing may include a matrix and silver nanowires doped therein. The silver nanowires overlap each other in the matrix to form a conductive network. The matrix refers to the non-nano-silver wire material formed by coating, heating and drying the solution containing the nano-silver wire. The silver nanowires are scattered or embedded in the matrix, and partly protrude from the matrix. The matrix can protect the silver nanowires from external environment such as corrosion and abrasion. In some embodiments, the matrix is compressible.

Please refer to pictures 2 to 4. FIG. 2 is a partial perspective view illustrating a bonding structure 110 according to an embodiment of the present disclosure. FIG. 3 is a partial side view showing the bonding structure 110 in FIG. 2 . FIG. 4 is a partial top view showing the bonding structure 110 in FIG. 2 . As shown in FIG. 2 to FIG. 4 , in this embodiment, the sensing region R1 and the bonding region R2 are defined on the substrate 111 . The optical film layer 114 has a first bonding opening O1 located in the bonding region R2. The portion of the first sensing electrode layer 112 extending to the sensing region R1 is covered by the optical film layer 114 , and the portion of the first sensing electrode layer 112 extending to the bonding region R2 is exposed by the first bonding opening O1 . The passivation layer 115 has a second bonding opening O2 located in the bonding region R2. The portion of the second sensing electrode layer 113 extending to the sensing region R1 is covered by the protection layer 115 , and the portion of the second sensing electrode layer 113 extending to the bonding region R2 is exposed by the second joint opening O2 of the protection layer 115 .

Please refer to FIG. 1A , in this embodiment, the flexible circuit board 120 includes a main body portion 121 , a first joint portion 122 and a second joint portion 123 . The first joint part 122 and the second joint part 123 extend from the edge of the main body part 121 . The first bonding part 122 bonds a portion of the first sensing electrode layer 112 exposed by the first bonding opening O1. The second bonding part 123 bonds a portion of the second sensing electrode layer 113 exposed by the second bonding opening O2.

In some embodiments, the first sensing electrode layer 112 includes a plurality of first-axis conductive units (not shown) separated from each other. The second sensing electrode layer 113 includes a plurality of second-axis conductive units (not shown) separated from each other. With the aforementioned structural configuration, touch signals (such as mutual capacitance sensing signals) between the first sensing electrode layer 112 and the second sensing electrode layer 113 can be extracted through the flexible circuit board 120 .

In particular, as shown in FIG. 2 to FIG. 4 , in this embodiment, the first joint opening O1 of the optical film layer 114 and the second joint opening O2 of the protective layer 115 are perpendicular to the first joint opening O2 of the substrate 111 . The surface 111a or the second surface 111b is misaligned in the direction D1. In other words, the first joint opening O1 and the second joint opening O2 do not overlap in the direction D1. In detail, as shown in FIG. 3, since the second surface 111b of the base material 111 is supported by the protective layer 115 at the position corresponding to the first joint opening O1, and the first surface 111a of the base material 111 corresponds to the second joint opening. The position of O2 is supported by the optical film layer 114 . With this structural configuration, the structural strength of the bonding region R2 of the substrate 111 can be effectively increased. In this way, the bonding structure 110 of this embodiment can effectively avoid cracks in the substrate 111 when the edge of the substrate 111 is hit, thereby ensuring that the first sensing electrode layer 112 and the second sensing electrode layer 112 disposed on the substrate 111 are connected to each other. Sensing function of the sensing electrode layer 113 .

Please refer to FIG. 5 , which is a partial cross-sectional view illustrating the bonding of the flexible circuit board 120 and the bonding structure 110 by using the indenter 300 . Specifically, FIG. 5 shows that the indenter 300 presses the second bonding portion 123 of the flexible circuit board 120 to the second sensing electrode layer 113 on the second surface 111 b of the substrate 111 . Although not shown, it can be understood that the first bonding portion 122 of the flexible circuit board 120 can also be pressed to the first sensing electrode layer 112 on the first surface 111 a of the substrate 111 by the pressure head 300 . As mentioned above, because the second surface 111b of the base material 111 is supported by the protective layer 115 at the position corresponding to the first joint opening O1, and the first surface 111a of the base material 111 is provided with an optical film at the position corresponding to the second joint opening O2. The layer 114 is supported, so the bonding region R2 of the substrate 111 can have greater structural strength to withstand the pressing force of the pressing head 300 . Thereby, the bonding structure 110 of this embodiment can effectively prevent cracks in the substrate 111 when the bonding region R2 of the substrate 111 is bonded to the flexible circuit board 120 , thereby ensuring that the first The signal transmission function of the sensing electrode layer 112 and the second sensing electrode layer 113 .

Please refer to FIG. 6 , which is a partial side view illustrating another joint structure 110' before improvement. As shown in FIG. 6, the bonding structure 110' includes a base material 111, a first sensing electrode layer 112, a second sensing electrode layer 113, an optical film layer 114' and a protective layer 115'. The first sensing electrode layer 112 is disposed on the upper surface of the substrate 111 . The optical film layer 114' covers the first sensing electrode layer 112. The second sensing electrode layer 113 is disposed on the lower surface of the substrate 111 . The protection layer 115' covers the second sensing electrode layer 113. Compared with the embodiment shown in FIG. 3 , the optical film layer 114 ′ of the bonding structure 110 ′ shown in FIG. 6 is used to expose the bonding opening of the first sensing electrode layer 112 to overlap the protective layer 115 ′. to expose the joint opening of the second sensing electrode layer 113 . In other words, the joint opening of the optical film layer 114' does not overlap with the protective layer 115', and the joint opening of the protective layer 115' does not overlap with the optical film layer 114' either. In the experiment of jointing with the flexible circuit board 120, the joint structure 110' shown in FIG. 6 has no local thickening at the joint opening, so the defect rate of cracks is 3.84%. In contrast, the bonding structure 110 shown in FIG. 3 is thickened by the protective layer 115 on the other side corresponding to the first bonding opening O1, and the substrate 111 is on the other side corresponding to the second bonding opening O2. The optical film layer 114 is thickened, so the defect rate of cracks can be reduced to zero; therefore, the preferred embodiment is shown in FIG. 3 .

In some embodiments, the substrate 111 is a flexible substrate. In some embodiments, the material of the substrate 111 includes Cyclo Olefin Polymer (COP), and the thickness of the substrate 111 is equal to or less than about 25 microns, but the present embodiment is not limited thereto. In some embodiments, the material of the substrate 111 includes colorless polyimide (CPI), and the thickness of the substrate 111 is equal to or less than about 12.5 microns, but the present embodiment is not limited thereto. In the case that the base material 111 is flexible and has a small thickness, the effect of improving the structural strength of the bonding region R2 of the base material 111 through the aforementioned structural configuration is more significant.

As shown in FIG. 3 , in this embodiment, the projection P1 of the first joint opening O1 of the optical film layer 114 in the direction D1 and the projection P2 of the second joint opening O2 of the protective layer 115 in the direction D1 are separated from each other. Viewed from another aspect, the optical film layer 114 and the protection layer 115 respectively have positions located between the first joint opening O1 and the second joint opening O2 in the direction D2 . These parts overlap in the direction D1. For example, the direction D2 is substantially parallel to the direction D1, but the disclosure is not limited thereto. By designing the optical film layer 114 and the protective layer 115 to have overlapping positions (in the direction D1) between the first joint opening O1 and the second joint opening O2, the joint region R2 of the substrate 111 can be further increased. structural strength.

Please refer to FIG. 7 , which is a schematic diagram illustrating an optical film layer 114 according to an embodiment of the present disclosure. As shown in FIG. 7, in this embodiment, the optical film layer 114 includes a pressure-sensitive adhesive layer 114a, a cover layer 114b, phase retarders 114c, 114d, and a polyvinyl alcohol layer 114e. The covering layer 114b is disposed on a side of the pressure-sensitive adhesive layer 114a away from the substrate 111 . The phase retarder 114c is disposed between the pressure-sensitive adhesive layer 114a and the covering layer 114b. The phase retarder 114d is disposed between the phase retarder 114c and the pressure-sensitive adhesive layer 114a. The polyvinyl alcohol layer 114e is disposed between the cover layer 114b and the phase retarder 114c.

In some implementations, the phase retarders 114c and 114d are half-wave plates and quarter-wave plates respectively, but the present disclosure is not limited thereto.

It should be noted that the conventional thickness of the optical film layer 114 is about 110 microns to about 150 microns. In some embodiments, the thickness of the optical film layer 114 can be reduced to about 60 microns to about 75 microns (eg, about 66 microns) for folding requirements, but the disclosure is not limited thereto. In some embodiments, the thickness of the pressure-sensitive adhesive layer 114 a is about 10 microns to about 20 microns (eg, about 15 microns), but the disclosure is not limited thereto. In some embodiments, the thickness of the covering layer 114b is about 35 microns to about 45 microns (eg, about 40 microns), but the disclosure is not limited thereto. In some embodiments, the thickness of the polyvinyl alcohol layer 114e is about 2 microns to about 8 microns (eg, about 5 microns), but the disclosure is not limited thereto.

Please refer to FIG. 8 , which is a schematic side view of an electronic device 200 according to another embodiment of the present disclosure. As shown in FIG. 8, in this embodiment, the electronic device 200 includes a bonding structure 110, a flexible circuit board 120, a display module 130, and a cover plate 140. These components are the same as those in the embodiment shown in FIG. 1A. Therefore, reference may be made to relevant descriptions above, and details are not repeated here. Compared with the embodiment shown in FIG. 1A , the electronic device 200 of this embodiment further includes a reinforcing layer 260 . The reinforcing layer 260 is disposed between the protective layer 115 of the bonding structure 110 and the display module 130 . Specifically, the reinforcement layer 260 is bonded to the protective layer 115 and fixed to the display module 130 through the adhesive layer 150a. For example, in an embodiment where the thickness of the substrate 111 is less than about 12.5 microns, the reinforcement layer 260 can additionally provide support for the substrate 111 in addition to the optical film layer 114 and the protective layer 115 .

Please refer to FIG. 9 , which is a schematic side view of an electronic device 200' according to another embodiment of the present disclosure. As shown in FIG. 9, in this embodiment, the electronic device 200' includes a bonding structure 110, a flexible circuit board 120, a display module 130, and a cover plate 140. These components are the same as those in the embodiment shown in FIG. 1A , so reference can be made to the relevant descriptions above, and details will not be repeated here. Compared with the embodiment shown in FIG. 1A, the electronic device 200' of this embodiment further includes a reinforcing layer 260'. The reinforcement layer 260' is disposed between the protective layer 115 of the bonding structure 110 and the display module 130. Specifically, the reinforcing layer 260' is attached to the protective layer 115, and is aligned with the adhesive layer 150a and attached to the bottom surface fixed to the protective layer 115 respectively. In other words, compared with the reinforcement layer 260 attached to the bottom surface of the protective layer 115 on the entire surface in FIG. Local reinforcement of structural strength.

From the above detailed description of the specific embodiments of the present disclosure, it can be clearly seen that in the joint structure and the electronic device of the present disclosure, by making the first joint opening of the optical film layer and the second joint opening of the protective layer The dislocation is substantially perpendicular to the direction of the substrate to achieve substantially local dislocation thickening, which can effectively increase the structural strength of the bonding area of the substrate. Thereby, when the edge of the substrate is hit or the bonding area is bonded with the flexible circuit board, cracks in the substrate can be effectively avoided, thereby ensuring that the first sensing electrode layer and the second sensing electrode layer disposed on the substrate are Measuring the sensing function and signal transmission function of the electrode layer.

Although the present disclosure has been disclosed above in terms of implementation, it is not intended to limit this disclosure. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of this disclosure. Therefore, the protection of this disclosure The scope shall be defined by the scope of the appended patent application.

100, 200, 200': Electronics 110,100': joint structure 111: Substrate 111a: first surface 111b: second surface 112: the first sensing electrode layer 113: the second sensing electrode layer 114,114': optical film layer 114a: pressure-sensitive adhesive layer 114b: Overlay 114c, 114d: phase delay film 114e: polyvinyl alcohol layer 115,115': protective layer 120:Flexible circuit board 121: Body Department 122: the first junction 123: second junction 130: display module 140: cover plate 150a, 150b: adhesive layer 260,260': reinforcement layer 300: pressure head D1, D2: direction O1: first joint opening O2: second joint opening P1, P2: Projection R1: Sensing area R2: Junction region

In order to make the above and other purposes, features, advantages and embodiments of the present disclosure more comprehensible, the accompanying drawings are described as follows: FIG. 1A is a schematic side view illustrating an electronic device according to an embodiment of the present disclosure. FIG. 1B is a partial cross-sectional view showing the electronic device in FIG. 1A , which corresponds to the position indicated by the line segment 1B-1B in FIG. 2 . FIG. 1C is another partial cross-sectional view of the electronic device in FIG. 1A , which corresponds to the position indicated by the line segment 1C-1C in FIG. 2 . FIG. 2 is a partial perspective view illustrating a bonding structure according to an embodiment of the present disclosure. FIG. 3 is a partial side view showing the bonding structure in FIG. 2 . FIG. 4 is a partial top view showing the bonding structure in FIG. 2 . FIG. 5 is a partial cross-sectional view illustrating the bonding of the flexible circuit board and the bonding structure by using a pressure head. FIG. 6 is a partial side view illustrating another bonding structure. FIG. 7 is a schematic diagram illustrating an optical film layer according to an embodiment of the present disclosure. FIG. 8 is a schematic side view of an electronic device according to another embodiment of the disclosure. FIG. 9 is a schematic side view of an electronic device according to another embodiment of the disclosure.

Domestic deposit information (please note in order of depositor, date, and number) none Overseas storage information (please note in order of storage country, institution, date, and number) none

110: joint structure

111: Substrate

112: the first sensing electrode layer

113: the second sensing electrode layer

114: Optical film layer

115: protective layer

O1: first joint opening

O2: second joint opening

R1: Sensing area

R2: Junction region

Claims (12)

A bonding structure, comprising: a substrate having a first surface and a second surface opposite to each other, a sensing region and a bonding region are defined on the substrate; a first sensing electrode layer disposed on the first surface; a second sensing electrode layer disposed on the second surface; an optical film layer covering the first sensing electrode layer and having a first joint opening located in the joint area; and a protective layer covering the second sensing electrode layer and having a second bonding opening located in the bonding region, Wherein the first joint opening and the second joint opening respectively expose a part of the first sensing electrode layer and a part of the second sensing electrode layer, and in a direction perpendicular to the first surface or the second surface dislocation. The junction structure according to claim 1, wherein projections of the first junction opening and the second junction opening in the direction are separated from each other. The bonding structure according to claim 1, wherein the optical film layer and the protective layer respectively have portions located between the first bonding opening and the second bonding opening, and these portions overlap in the direction. The bonding structure according to claim 1, wherein at least one of the first sensing electrode layer and the second sensing electrode layer is a nano silver wire electrode layer. The joint structure according to claim 1, wherein the substrate is a flexible substrate. The bonding structure according to claim 1, wherein the material of the substrate comprises cycloolefin polymer, and the thickness of the substrate is equal to or less than 25 micrometers. The bonding structure according to claim 1, wherein the material of the substrate comprises colorless polyimide, and the thickness of the substrate is equal to or less than 12.5 microns. The bonding structure as claimed in item 1, wherein the optical film layer comprises: a pressure-sensitive adhesive layer; a cover layer, disposed on the side of the pressure-sensitive adhesive layer away from the substrate; at least one phase retarder disposed between the pressure-sensitive adhesive layer and the cover layer; and A polyvinyl alcohol layer is disposed between the cover layer and the at least one phase retarder. An electronic device comprising: A joint structure as described in any one of Claims 1 to 8; A flexible circuit board includes a first joint portion and a second joint portion, the first joint portion joints the portion of the first sensing electrode layer exposed by the first joint opening, and the second joint portion bonding the portion of the second sensing electrode layer exposed by the second bonding opening; a display module, disposed on the side of the protective layer away from the substrate; and A cover plate is arranged on the side of the optical film layer away from the base material. The electronic device as described in Claim 9, further comprising: A reinforcement layer is arranged between the protective layer and the display module. The electronic device as described in claim 10, further comprising: An adhesive layer is arranged between the reinforcing layer and the display module. The electronic device as described in claim 10, further comprising: An adhesive layer is arranged between the protective layer and the display module, and is arranged side by side with the reinforcing layer.

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